METAL PLUG FORMATION BY EXCIMER LASER-INDUCED MELTING FOR SUBMICRON INTERCONNECT

A new laser planarization technique for producing metal plugs has been developed. In this technique, a thin metal film is patterned to be covering enough the entire via hole. The patterning controlles the total amount of metal which is filled in the via hole. A metal cap is fabricated by this patterning, followed by melting with a XeCl excimer laser irradiation. The molten metal cap is drawn to the via during the mass transport procedure, resulting in formation of the metal plug. The mass transport mechanism of molten has been cleared up. The mass transport for the plug formation is attributed to the surface tension forces created by the three-dimensional geometry of the molten metal. The use of metal cap brings that the plug formation is performed easily and stably. And further, this technique is an effective method for submicron interconnection. The interconnects on contact check device are improved by the plug formation. The contact check device is composed of 60000 vias connected in series. These characteristics agree well with the results calculated using electrical resistivity of metal.